Buffered and Registered Memory: Is it worth the expense?

Hey guys.

As the subject says, I'm pricing up some RAM. I'm looking for 2GB of
PC2-8500 and I'm coming across modules that are either "buffered" or
"unbuffered" and "registered" or "un-registered".

I've found a website that explains what these mean, and it seems to
emphasise that buffered and registered memory is only necessary in:

"servers and other mission-critical systems where it is extremely
important that the data is properly handled."

For an average consumer such as myself, should I save some pennies and
get unbuffered and unregistered RAM, or is their a genuine benefit to me?

Kind Regards,

Matt

In alt.comp.hardware.pc-homebuilt Matt wrote:

For an average consumer such as myself, should I save some pennies and
get unbuffered and unregistered RAM, or is their a genuine benefit to me?

*IF* your motherboard supports buffered and registered ECC RAM, then get
ECC RAM. If not, then don't bother. Most don't (but should). ;-{

--
_____
/ ' / â„¢
,-/-, __ __. ____ /_
(_/ / (_(_/|_/ / _/ _

Matt wrote:
Hey guys.

As the subject says, I'm pricing up some RAM. I'm looking for 2GB of
PC2-8500 and I'm coming across modules that are either "buffered" or
"unbuffered" and "registered" or "un-registered".

I've found a website that explains what these mean, and it seems to
emphasise that buffered and registered memory is only necessary in:

"servers and other mission-critical systems where it is extremely
important that the data is properly handled."

For an average consumer such as myself, should I save some pennies and
get unbuffered and unregistered RAM, or is their a genuine benefit to me?

Kind Regards,

Matt

Registered memory, adds a register chip between the memory chips on the
DIMM, and the control/address bus. The purpose of doing that, is to reduce
the electrical load on the control/address bus.

By doing that, you can put more DIMMs on the same bus. That is handy for
building server boards, as they tend to have more DIMM slots than desktop
boards.

Unbuffered memory doesn't have the register chip in the path.

The other feature involves the data bit organization.

Memory equipped with check bits, allows errors to be detected or to be
corrected. Examples of methods are simple parity and ECC.

Not all chipsets have support for ECC. The X38 has support, but we're not
sure at this point, that it actually works. (The first report I've seen
so far, showed trouble when ECC DIMMs were used on an X38.)

If a user selects ECC equipped DDR2, at the moment that means using a
slower grade of module. Perhaps DDR2-667 would be the speed you'd expect
from an ECC equipped product - this is mainly because there is no interest
in the enthusiast market, for using ECC DIMMs.

The Athlon64 has the memory controller inside the processor itself, and
the chip supports a grand total of 144 bits of data. That is enough for
two 72 bit wide DIMMs. One of the options offered, is a protection method
called "Chip Kill", which has enough redundancy so that if a x4 wide memory
chip died, the memory could still function.

So a chip like the Athlon64 ensures that AMD users have an opportunity with
any motherboard, to have support for the extra check bits on an ECC module.
On Intel, the chipset must be specifically designed with the extra bits
added. And the practice in recent generations, has been for the most part
to not include the extra bits, on chipsets intended for Intel processors.
My 875P based board (DDR era) has ECC capability, but a lot of stuff more
modern than that does not. The X38 only supports ECC on DDR2, and the ECC
feature is missing if you buy an X38 with DDR3. It isn't even clear to me
yet, whether DDR3 has room for an ECC chip on it or not - I haven't seen a
DDR3 module with ECC included. (And navigating the JEDEC site is no fun, which
is why I haven't investigated further.)

While there is certainly value in having the ability to check the integrity
of data stored in the RAM, the industry is not making it easy for a desktop
user to get that feature. You have to decide what that is worth, as it affects
a few buying decisions.

Paul

"Matt" wrote...

As the subject says, I'm pricing up some RAM. I'm looking for 2GB of PC2-8500
and I'm coming across modules that are either "buffered" or "unbuffered" and
"registered" or "un-registered".

For an average consumer such as myself, should I save some pennies and get
unbuffered and unregistered RAM, or is their a genuine benefit to me?

Get what the motherboard supports. Most consumer-grade MoBos support
unregistered RAM. Opteron MoBos (especially multiple-socket types) normally
support buffered/registered RAM. Many/most server MoBos support or require ECC
RAM.

Generally, if it is not required, buffered/registered or ECC RAM is not worth
the extra cost for consumer machines.

John Weiss wrote:

.... snip ...

Generally, if it is not required, buffered/registered or ECC RAM
is not worth the extra cost for consumer machines.

This misinformation needs to be squelched. ALWAYS get ECC memory
if your system supports it, and try to buy systems that support it.

There is no checking mechananism other than ECC available for
memory, and random memory failures, such as caused by cosmic rays,
can be fatal. The fault may not show up for weeks or months (or
more) after occuring, and such things as memtestXX will show no
fault. By this time all your backups are fouled.

The extra cost is very small, about 1/8 to 1/5 of the cost of the
simpler, faulty memory.

--
Chuck F (cbfalconer at maineline dot net)
http://cbfalconer.home.att.net
Try the download section.



--
Posted via a free Usenet account from http://www.teranews.com

RobV wrote:
Frank McCoy wrote:
Matt wrote:

For an average consumer such as myself, should I save some
pennies and get unbuffered and unregistered RAM, or is their
a genuine benefit to me?

*IF* your motherboard supports buffered and registered ECC RAM,
then get ECC RAM. If not, then don't bother. Most don't (but
should). ;-{

Doesn't the cache on the CPU (L1 and L2) have ECC? At one time,
at least, I thought I read it did. However, just like Al Dykes,
my wetware is showing the problem of years of cosmic (and other)
rays over the years.

Far from guaranteed. Investigate the potential purchase carefully.

--
Chuck F (cbfalconer at maineline dot net)
http://cbfalconer.home.att.net
Try the download section.



--
Posted via a free Usenet account from http://www.teranews.com

Most home PCs don't need registered / buffered memory. My main home PC has 2 DIMMs with 9 memory chips on each DIMM and it work fine. I have seen PCs at work with 4 DIMMs with 36 memory chips on each DIMM. It is unlikely that the memory bus would drive all these chips if they were not buffered.

Paul wrote:

Registered memory, adds a register chip between the memory chips on the
DIMM, and the control/address bus. The purpose of doing that, is to reduce
the electrical load on the control/address bus.

By doing that, you can put more DIMMs on the same bus. That is handy for
building server boards, as they tend to have more DIMM slots than desktop
boards.

--
Mike Walsh

On Tue, 8 Jan 2008 23:37:03 -0500, "RobV"
wrote:

Frank McCoy wrote:
In alt.comp.hardware.pc-homebuilt Matt
wrote:

For an average consumer such as myself, should I save some pennies
and get unbuffered and unregistered RAM, or is their a genuine
benefit to me?

*IF* your motherboard supports buffered and registered ECC RAM, then
get ECC RAM. If not, then don't bother. Most don't (but should).
;-{

Doesn't the cache on the CPU (L1 and L2) have ECC? At one time, at
least, I thought I read it did. However, just like Al Dykes, my wetware
is showing the problem of years of cosmic ( and other) rays over the
years.



Yes they do, though one having ECC is not a substitute for
the other.